When the book of Revelation calls Jesus (Yeshua‘) the Root of David, it emphasizes that, as David’s root, Jesus preceded David. David sprung forth from Jesus, but Jesus is also the source and purpose of David’s life. The name Root and descendant of David includes both aspects.
Root of David in Greek:
Hē rhiza Dauid
Strong’s Concordance numbers: 4491, 1160b
Bible reference: Rev. 5:5
And one of the elders saith unto me, Weep not: behold, the Lion of the tribe of Judah, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof. (Revelation 5:5 KJV)
A similar name of Jesus in both Testaments is the Root of Jesse.